Truly living polymerization, i.e., truly terminationless and chain transferless polymerizations, are a most desirable objective of the synthetic polymer chemist. If the rates of both termination and chain transfer are zero, R.sub.t =R.sub.tr =0, and the rate of initiation is larger than that of propagation R.sub.i &gt;R.sub.p, polymer molecule weights are determined by the ratio [M]/[I] (i.e., monomer over initiator concentrations) and M.sub.w /M.sub.n will be reasonably small. If R.sub.i is instantaneous and/or R.sub.i &gt;&gt;R.sub.p, then M.sub.w /M.sub.n .about.1.0. Living polymerizations are not only of scientific interest, but also of great commercial consequence, and several industrial processes are based on living systems, e.g., cis-1,4-polybutadiene, triblock copolymers of styrene/butadiene/styrene, polytetrahydrofuran, but these are not carbocationic polymerization processes.
Although great efforts have been made to develop living carbocationic polymerizations, success remains rather limited. The only truly living carbocationic systems described to date are those achieved by Higashimura, Sawamoto, et al. involving the HI/I.sub.2 initiator system and the highly cationically reactive monomers such as vinyl ethers, p-methoxy styrene and N-vinyl carbazole. Under certain well-defined experimental conditions, quasiliving carbocationic polymerizations approach those of truly living polymerizations but only under quite restrictive conditions, i.e., very low temperatures, continuous slow monomer addition (when the rate of monomer addition and that of monomers consumption are equal), and even then the rate of chain transfer is not exactly zero, but only approaches zero. Also, in quasiliving polymerizations, R.sub.t is not zero, but termination is reversible so that over a reasonably long time period termination appears to be absent, hence the term "quasiliving."